Forensic Liu Xiaohui's girlfriend was eventually killed, while Liu Xiaohui's girlfriend Xu Shan was killed in 2008. The body could not be found, leaving only a broken hand at the scene. Liu Xiaohui, who was in a hurry to solve the case, illegally sent the broken hand and the only DNA left by the murderer suspect for inspection. Because of careless custody, DNA failed, and the only clue was broken, which led to the case being unsolved so far. Liu Xiaohui regretted it, and this case became an inextricable knot in his heart.